Classifier type coal mills utilize pressure rollers which rotate over the holding surface of a rotating bowl onto which lump coal is fed so as to be crushed by interaction between the rollers and the bowl surface. The rollers are supported by journals having spring suspension systems. The journals and the suspension systems are subject to harsh abrasive wear as a result of the impingement of milled coal carried into contact with the journal and suspension system components by a stream of air which flows upwardly through the mill to perform a classifier function.
In this environment coal mill journals and suspension components wear away in a relatively uneven fashion to create rough outer surfaces and eventually to weaken the structural components to the point where they must be replaced.
In the past it has been common to protect the journal and associated components by welding custom cut wear plates to the eroded surfaces of the journal and suspension housings. Because each journal housing wears in a somewhat different fashion, liner wear plates have to be cut and fit in a laborious fashion. The attachment process is made more difficult by the fact that most journal housing surfaces are curved whereas the wear plates are cut from larger plates which are entirely flat. In many cases, the journal is so severely worn that insufficient material remains to level off the surface without further weakening it. The result is high expense in the process of attaching the wear materials and, in many cases, premature replacement of journal components.